/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
// $Id: JAXPPrefixResolver.java,v 1.1.2.1 2005/08/01 01:30:18 jeffsuttor Exp $

package com.sun.org.apache.xpath.internal.jaxp;

import org.w3c.dom.Node;
import org.w3c.dom.NamedNodeMap;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;

import javax.xml.namespace.NamespaceContext;

/**
 * <meta name="usage" content="general"/>
 * This class implements a Default PrefixResolver which
 * can be used to perform prefix-to-namespace lookup
 * for the XPath object.
 * This class delegates the resolution to the passed NamespaceContext
 */
public class JAXPPrefixResolver implements PrefixResolver {

  private NamespaceContext namespaceContext;


  public JAXPPrefixResolver(NamespaceContext nsContext) {
    this.namespaceContext = nsContext;
  }


  public String getNamespaceForPrefix(String prefix) {
    return namespaceContext.getNamespaceURI(prefix);
  }

  /**
   * Return the base identifier.
   *
   * @return null
   */
  public String getBaseIdentifier() {
    return null;
  }

  /**
   * @see PrefixResolver#handlesNullPrefixes()
   */
  public boolean handlesNullPrefixes() {
    return false;
  }


  /**
   * The URI for the XML namespace.
   * (Duplicate of that found in com.sun.org.apache.xpath.internal.XPathContext).
   */

  public static final String S_XMLNAMESPACEURI =
      "http://www.w3.org/XML/1998/namespace";


  /**
   * Given a prefix and a Context Node, get the corresponding namespace.
   * Warning: This will not work correctly if namespaceContext
   * is an attribute node.
   *
   * @param prefix Prefix to resolve.
   * @param namespaceContext Node from which to start searching for a xmlns attribute that binds a
   * prefix to a namespace.
   * @return Namespace that prefix resolves to, or null if prefix is not bound.
   */
  public String getNamespaceForPrefix(String prefix,
      org.w3c.dom.Node namespaceContext) {
    Node parent = namespaceContext;
    String namespace = null;

    if (prefix.equals("xml")) {
      namespace = S_XMLNAMESPACEURI;
    } else {
      int type;

      while ((null != parent) && (null == namespace)
          && (((type = parent.getNodeType()) == Node.ELEMENT_NODE)
          || (type == Node.ENTITY_REFERENCE_NODE))) {

        if (type == Node.ELEMENT_NODE) {
          NamedNodeMap nnm = parent.getAttributes();

          for (int i = 0; i < nnm.getLength(); i++) {
            Node attr = nnm.item(i);
            String aname = attr.getNodeName();
            boolean isPrefix = aname.startsWith("xmlns:");

            if (isPrefix || aname.equals("xmlns")) {
              int index = aname.indexOf(':');
              String p = isPrefix ? aname.substring(index + 1) : "";

              if (p.equals(prefix)) {
                namespace = attr.getNodeValue();
                break;
              }
            }
          }
        }

        parent = parent.getParentNode();
      }
    }
    return namespace;
  }

}
